2.1 G is not a hard landing. G meters can not determine a landing force. The meters get jarred just like dropping a clock so show erroneous readings. The only way to measure a landing is by the rate of descent at touch down. From memory only, the CS25 minimum standard is 650'/min and most a/c are certified to 850'/min which means you can fly the ILS straight into the runway without any flare at all and still not do a heavy landing. approx 750'/min equate to 3g in your terms.
The main cause of heavy landings is people flaring, floating then loosing lift and dropping like a stone. Bad technique. If you flare and let it settle you will never ever do a hard landing in your life.